The killer, who came to be known as the “Phantom of Heilbronn,” was actually the result of a critical forensic error.

Rex Heuermann, 62, entered the pleas in a courtroom packed with reporters, police and victims' relatives, some of whom wept as he detailed his crimes for the court. He will be sentenced to life in prison without the possibility of parole at a later date.

Heuermann, who lived with his wife and two children in a small home in Massapequa Park, was arrested July 13, 2023 and charged with the deaths of Melissa Barthelemy, Megan Waterman and Amber Lynn Costello. In 2024 he was charged with killing Maureen Brainard-Barnes, Jessica Taylor and Sandra Costilla, and later in the year, Mack.

The notorious serial killer pleaded guilty to eight deaths, and he made a chilling revelation during the court hearing. The Suffolk County DA asked Heuermann, a married architect and father, how he killed the women. “Strangulation,” he responded, according to CNN. But that’s not all.

"Serial Killer: The Exhibition" will now run through May 31 at Pullman Yards, drawing thousands of visitors, long stays, and more than 20 reported fainting episodes.

These projects reveal the evil lurking underneath the guises of killers who were so often hiding in plain sight.

Long Island Serial Killer Rex Heuermann is expected to detail the seven murders he’s charged with when he amends his plea, Us Weekly can exclusively report